Ecu Self-Diagnostic Function; Self-Diagnostic Function Table - Yamaha FX10X 2008 Service Manual

ECU SELF-DIAGNOSTIC FUNCTION

The ECU is equipped with a self-diagnostic function in order to ensure that the fuel injection system is operat-
ing normally. If this function detects a malfunction in the system, it immediately operates the engine under
substitute characteristics and the warning light and self-diagnostic warning indicator on the LCD flash to alert
the rider that a malfunction has occurred in the system. Once a malfunction has been detected, a fault code is
stored in the memory of the ECU.
• If a malfunction is detected in the system by the self-diagnostic function, the ECU provides an appropriate
substitute characteristic operation, and the warning light and self-diagnostic warning indicator on the LCD
flash to alert the rider of the detected malfunction.
• The lowest fault code number appears on the odometer/tripmeter/engine speed meter LCD. Once a fault
code has been displayed, it remains stored in the memory of the ECU until it is deleted.

SELF-DIAGNOSTIC FUNCTION TABLE

If the ECU detects an abnormal signal from a sensor while the snowmobile is being driven, the warning light
and self-diagnostic warning indicator on the LCD flash to alert the rider that a malfunction has occurred and
the ECU provides the engine with alternate operating instructions that are appropriate for the type of malfunc-
tion.
When an abnormal signal is received from a sensor, the ECU processes the specified values that are pro-
grammed for each sensor in order to provide the engine with alternate operating instructions that enable the
engine to continue to operate or stop operating, depending on the conditions.
Self-Diagnostic-Function table
Fault code
No.
Crankshaft position sensor
12
Intake air pressure sensor 1 (cylinders #1,
13
#2, and #3) (open or short circuit)
Intake air pressure sensor 1 (cylinders #1,
14
#2, and #3) (hose line)
Throttle position sensor (open or short cir-
15
cuit)
16 Throttle position sensor (stuck)
Coolant temperature sensor
21
Intake air temperature sensor
22
Intake air pressure sensor 2 (cylinder #1)
25
(open or short circuit)
Intake air pressure sensor 2 (cylinder #1)
26
(hose line)
Oil pressure dropped
30
Cylinder-#1 ignition coil (faulty ignition)
33
Cylinder-#2 ignition coil (faulty ignition)
34
Cylinder-#3 ignition coil (faulty ignition)
35
FUEL INJECTION SYSTEM
Item
No normal signals are received from the
crankshaft position sensor.
Intake air pressure sensor: open or short
circuit detected.
Intake air pressure sensor: hose system
malfunction (clogged or detached hose).
Throttle position sensor: open or short cir-
cuit detected.
Stuck throttle position sensor detected.
Coolant temperature sensor: open or short
circuit detected.
Intake air temperature sensor: open or
short circuit detected.
Intake air pressure sensor: open or short
circuit detected.
Intake air pressure sensor: hose system
malfunction (clogged or detached hose).
Engine stops when an oil pressure drop is
detected.
Malfunction detected in the primary lead of
the cylinder-#1 ignition coil.
Malfunction detected in the primary lead of
the cylinder-#2 ignition coil.
Malfunction detected in the primary lead of
the cylinder-#3 ignition coil.
Symptom
7-4
FI
Able/unable Able/unable
to start to drive
Unable Unable
Able Able
Able Able
Able Able
Able Able
Able Able
Able Able
Able Able
Able Able
Unable Unable
Able Able
(depending (depending
on the num- on the num-
ber of faulty ber of faulty
cylinders) cylinders)
Able Able
(depending (depending
on the num- on the num-
ber of faulty ber of faulty
cylinders) cylinders)
Able Able
(depending (depending
on the num- on the num-
ber of faulty ber of faulty
cylinders) cylinders)